Here is the full list of all 21 Misao: Definitive Edition achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Clear Truth with the female protagonist.
Clear Truth with the male protagonist.
Free Kurata in the Truth route.
Give Misao some coins
Clear the main game with the male protagonist.
Talk with Library multiple times.
Encounter Hanako.
Hide in a cardboard box.
See the bad ending.
Clear the main game with the female protagonist
Save Kudoh.
Find the message in the back of the laboratory.
Play the piano.
Jump off the rooftop.
Refuse to help Yoshino.
Read "The Lazy-Eyed Ranger."
Read the diary in the library.
Have a meal.
Get a whiff of a toilet.
Check your key items.
Make a quicksave.